An original Thinka practice paper modelled on the structure and difficulty of the Nov 2024 Cambridge International A Level Mathematics (Specification A) paper. Not affiliated with or reproduced from Cambridge.
Paper 1H
Answer all 25 questions. Write your working clearly. Calculators may be used.
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Worked solution
To simplify the fraction, we factorise both the numerator and the denominator. The numerator is a quadratic: \(2x^2 - 5x - 3 = (2x + 1)(x - 3)\). The denominator can first be factorised by taking out the common factor of 2: \(2x^2 - 18 = 2(x^2 - 9)\). We then recognise the difference of two squares in the bracket: \(x^2 - 9 = (x - 3)(x + 3)\), which gives the fully factorised denominator as \(2(x - 3)(x + 3)\). Writing the fraction with these factorised forms, we get \(\frac{(2x + 1)(x - 3)}{2(x - 3)(x + 3)}\). Cancelling the common factor of \((x - 3)\) from the numerator and denominator gives \(\frac{2x + 1}{2(x + 3)}\), which can also be written as \(\frac{2x + 1}{2x + 6}\).
Marking scheme
M1 for factorising the numerator as \((2x + 1)(x - 3)\) (or equivalent). M1 for factorising the denominator by taking out 2, i.e., \(2(x^2 - 9)\). M1 for fully factorising the denominator as \(2(x - 3)(x + 3)\). A1 for the correct simplified fraction \(\frac{2x+1}{2x+6}\) or \(\frac{2x+1}{2(x+3)}\).
Question 2 · Structured
4 marks
A cuboid has dimensions \(AB = 8\text{ cm}\), \(BC = 6\text{ cm}\), and height \(CG = 12\text{ cm}\). Calculate the angle that the diagonal \(AG\) makes with the base \(ABCD\). Give your answer correct to 1 decimal place.
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Worked solution
First, we find the length of the diagonal of the base, \(AC\), using Pythagoras' Theorem in the right-angled triangle \(ABC\): \(AC^2 = AB^2 + BC^2 = 8^2 + 6^2 = 64 + 36 = 100\), so \(AC = \sqrt{100} = 10\text{ cm}\). Next, we consider the right-angled triangle \(ACG\), where the angle \(\angle GAC\) is the angle that the diagonal \(AG\) makes with the base. Using trigonometry: \(\tan(\angle GAC) = \frac{\text{opposite}}{\text{adjacent}} = \frac{CG}{AC} = \frac{12}{10} = 1.2\). Therefore, \(\angle GAC = \tan^{-1}(1.2) = 50.1944...^\circ\). Correct to 1 decimal place, the angle is \(50.2^\circ\).
Marking scheme
M1 for using Pythagoras' Theorem to calculate the base diagonal length \(AC^2 = 8^2 + 6^2\). A1 for obtaining \(AC = 10\). M1 for setting up a correct trigonometric ratio, e.g., \(\tan(\theta) = \frac{12}{10}\). A1 for a correct final answer of 50.2 (accept answers in range 50.1 to 50.3).
Question 3 · Structured
4 marks
Liam invests a sum of money in a savings account that pays compound interest at a rate of \(2.5\%\) per annum. At the end of 3 years, the value of the investment is \(\pounds 8615.12\). Calculate the amount of money Liam originally invested. Give your answer correct to the nearest penny.
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Worked solution
Let the original amount invested be \(P\). With compound interest of \(2.5\%\) per year, the value of the investment after 3 years is given by \(P \times 1.025^3\). We set up the equation: \(P \times 1.025^3 = 8615.12\). Rearranging to solve for \(P\), we get: \(P = \frac{8615.12}{1.025^3} = \frac{8615.12}{1.076890625} = 8000.0016...\). Rounding to the nearest penny gives \(\pounds 8000.00\).
Marking scheme
M1 for identifying the multiplier \(1.025\). M1 for setting up the equation \(P \times 1.025^3 = 8615.12\). M1 for rearranging the equation to solve for \(P\), e.g., \(P = \frac{8615.12}{1.025^3}\). A1 for the correct final answer of 8000.00 (or 8000).
Question 4 · Structured
4 marks
In triangle \(PQR\), \(PQ = 7.4\text{ cm}\), \(QR = 11.2\text{ cm}\), and angle \(PQR = 115^\circ\). Calculate the length of \(PR\). Give your answer correct to 3 significant figures.
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Worked solution
We use the Cosine Rule to find the length of \(PR\): \(PR^2 = PQ^2 + QR^2 - 2 \times PQ \times QR \times \cos(\angle PQR)\). Substituting the given values: \(PR^2 = 7.4^2 + 11.2^2 - 2 \times 7.4 \times 11.2 \times \cos(115^\circ)\). This simplifies to: \(PR^2 = 54.76 + 125.44 - 165.76 \times (-0.422618...)\) which gives \(PR^2 = 180.20 + 70.053... = 250.253...\). Taking the square root: \(PR = \sqrt{250.253...} = 15.819...\). Correct to 3 significant figures, the length is \(15.8\text{ cm}\).
Marking scheme
M1 for substituting the correct values into the Cosine Rule: \(7.4^2 + 11.2^2 - 2 \times 7.4 \times 11.2 \times \cos(115)\). A1 for evaluating intermediate steps to obtain \(PR^2 \approx 250.25\). M1 for taking the square root of their value of \(PR^2\). A1 for a correct final answer of 15.8 (accept answers in range 15.8 to 15.82).
Question 5 · Structured
4 marks
In a sale, the price of a coat is reduced by \(20\%\). The sale price of the coat is then reduced by a further \(15\%\) during a clearance event. The final clearance price of the coat is \(\pounds 102\). Calculate the original price of the coat before any reductions.
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Worked solution
Let the original price of the coat be \(X\). A reduction of \(20\%\) is represented by multiplying by \(0.80\). A further reduction of \(15\%\) on this sale price is represented by multiplying by \(0.85\). Therefore, the overall multiplier is \(0.80 \times 0.85 = 0.68\). We can set up the equation: \(0.68 \times X = 102\). Solving for \(X\): \(X = \frac{102}{0.68} = 150\). Thus, the original price was \(\pounds 150\).
Marking scheme
M1 for writing a multiplier of \(0.80\) (or \(80\%\)) or \(0.85\) (or \(85\%\)). M1 for the combined multiplier \(0.80 \times 0.85 = 0.68\) (or equivalent method such as working backwards in two separate steps, e.g., \(102 \div 0.85 = 120\)). M1 for setting up the equation \(0.68X = 102\) or dividing \(120 \div 0.8\). A1 for the correct final answer of 150.
Question 6 · Structured
4 marks
Rearrange the formula \(y = \frac{4x + 3}{2 - x}\) to make \(x\) the subject.
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Worked solution
To make \(x\) the subject, we first multiply both sides by \((2 - x)\) to clear the fraction: \(y(2 - x) = 4x + 3\). Expanding the bracket gives: \(2y - xy = 4x + 3\). Next, we gather all terms containing \(x\) on one side and other terms on the other side: \(2y - 3 = 4x + xy\). Factoring out \(x\) on the right side: \(2y - 3 = x(4 + y)\). Finally, we divide by \((4 + y)\) to isolate \(x\): \(x = \frac{2y - 3}{4 + y}\).
Marking scheme
M1 for multiplying both sides by \((2 - x)\) to get \(y(2 - x) = 4x + 3\). M1 for expanding the bracket correctly to get \(2y - xy = 4x + 3\). M1 for isolating terms with \(x\) on one side and factorising to get \(x(4 + y) = 2y - 3\) (or equivalent). A1 for the correct final formula \(x = \frac{2y - 3}{4 + y}\) or equivalent.
Question 7 · Structured
4 marks
A rectangle has a length of \((2x + 5)\text{ cm}\) and a width of \((x - 1)\text{ cm}\). Given that the area of the rectangle is \(30\text{ cm}^2\), find the value of \(x\). Show your working clearly.
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Worked solution
The area of a rectangle is length times width, so: \((2x + 5)(x - 1) = 30\). Expanding the brackets: \(2x^2 - 2x + 5x - 5 = 30\), which simplifies to \(2x^2 + 3x - 5 = 30\). Subtracting 30 from both sides gives the quadratic equation: \(2x^2 + 3x - 35 = 0\). We can solve this by factorising. We need two numbers that multiply to \(2 \times (-35) = -70\) and add to 3. These numbers are 10 and -7. Thus, \(2x^2 + 10x - 7x - 35 = 0 \implies 2x(x + 5) - 7(x + 5) = 0 \implies (2x - 7)(x + 5) = 0\). This gives two possible solutions: \(2x - 7 = 0 \implies x = 3.5\) or \(x + 5 = 0 \implies x = -5\). Since the width of a rectangle must be positive, \(x - 1 = -5 - 1 = -6\) is impossible, so we discard \(x = -5\). Therefore, \(x = 3.5\).
Marking scheme
M1 for setting up the equation \((2x + 5)(x - 1) = 30\). M1 for expanding brackets and rearranging to form the quadratic equation \(2x^2 + 3x - 35 = 0\). M1 for solving the quadratic equation to get \(x = 3.5\) and \(x = -5\) (by factorisation, formula, or completing the square). A1 for identifying \(x = 3.5\) as the only valid solution.
Question 8 · Structured
4 marks
The functions \(f\) and \(g\) are defined as \(f(x) = \frac{3}{x - 2}\) for \(x \neq 2\) and \(g(x) = 2x + 5\). Find the value of \(x\) for which \(fg(x) = \frac{1}{3}\).
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Worked solution
We start by finding the expression for the composite function \(fg(x)\), which means substituting \(g(x)\) into \(f(x)\): \(fg(x) = f(g(x)) = f(2x + 5) = \frac{3}{(2x + 5) - 2} = \frac{3}{2x + 3}\). Next, we set this expression equal to \(\frac{1}{3}\): \(\frac{3}{2x + 3} = \frac{1}{3}\). Multiplying both sides by \(3(2x + 3)\) to clear the denominators gives: \(3 \times 3 = 1 \times (2x + 3) \implies 9 = 2x + 3\). Subtracting 3 from both sides gives \(2x = 6\), and dividing by 2 gives \(x = 3\).
Marking scheme
M1 for attempting to find the composite function \(fg(x)\) by substituting \(g(x)\) into \(f(x)\). A1 for simplifying the composite function to \(\frac{3}{2x + 3}\). M1 for setting up the equation \(\frac{3}{2x + 3} = \frac{1}{3}\) and converting it to a linear equation, e.g., \(2x + 3 = 9\). A1 for the correct final answer of 3.
M1 for factorising \(6x^2 - 7x - 3\) correctly as \((3x + 1)(2x - 3)\) or \(9x^2 - 1\) as \((3x - 1)(3x + 1)\)
M1 for factorising \(2x^2 - 5x + 3\) correctly as \((2x - 3)(x - 1)\) or \(x^2 - 2x + 1\) as \((x - 1)^2\)
M1 for multiplying by the reciprocal and showing intention to cancel common terms
A1 for the fully simplified fraction \(\frac{x-1}{3x-1}\)
Question 10 · Structured
4 marks
\(ABCD\) is a horizontal rectangle with \(AB = 6\text{ cm}\) and \(BC = 8\text{ cm}\). The rectangle \(EFGH\) is directly above \(ABCD\) such that \(AE\), \(BF\), \(CG\), and \(DH\) are vertical edges of a cuboid, each of length \(12\text{ cm}\). Calculate the size of the angle that the diagonal line \(AG\) makes with the horizontal plane \(ABCD\). Give your answer correct to 1 decimal place.
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Worked solution
First, find the length of the diagonal \(AC\) on the horizontal base \(ABCD\) using Pythagoras' Theorem:
\(AC^2 = AB^2 + BC^2\)
\(AC^2 = 6^2 + 8^2 = 36 + 64 = 100\)
\(AC = \sqrt{100} = 10\text{ cm}\)
The angle that the line \(AG\) makes with the plane \(ABCD\) is the angle \(GAC\) in the right-angled triangle \(ACG\).
In triangle \(ACG\), \(CG = 12\text{ cm}\) (opposite side) and \(AC = 10\text{ cm}\) (adjacent side).
M1 for calculating the length of the diagonal \(AC\) as \(10\text{ cm}\) (or showing \(AC = \sqrt{6^2 + 8^2}\))
M1 for setting up a correct trigonometric ratio to find the angle, e.g., \(\tan(\theta) = \frac{12}{10}\) or \(\sin(\theta) = \frac{12}{AG}\) with a calculation of \(AG = \sqrt{244}\)
M1 for attempting to find the angle using inverse trigonometric functions, e.g., \(\theta = \tan^{-1}(1.2)\)
A1 for \(50.2\) (accept answers in the range \(50.19\) to \(50.2\))
Question 11 · Structured
4 marks
In a sale, normal prices are reduced by 15%.
The sale price of a laptop is then reduced by a further 10%.
After both reductions, the price of the laptop is £535.50.
Calculate the normal price of the laptop before any reductions.
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In triangle \(ABC\), \(AB = 7\text{ cm}\), \(AC = 9\text{ cm}\), and angle \(BAC = 64^\circ\). Calculate the perimeter of triangle \(ABC\). Give your answer correct to 3 significant figures.
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Worked solution
Use the Cosine Rule to find the length of the third side \(BC\):
\(BC^2 = AB^2 + AC^2 - 2 \times AB \times AC \times \cos(BAC)\)
To 3 significant figures, this is \(24.6\text{ cm\}.
Marking scheme
M1 for substituting the given values correctly into the Cosine Rule: \(BC^2 = 7^2 + 9^2 - 2 \times 7 \times 9 \times \cos(64^\circ)\)
M1 for correct evaluation of \(BC^2\) (approx. \(74.8\)) or \(BC\) (approx. \(8.65\))
M1 for adding the three side lengths together: \(7 + 9 + \text{their } BC\)
A1 for \(24.6\) (accept answers in the range \(24.6\) to \(24.7\))
Question 14 · Structured
4 marks
Company A has 150 employees. 60% of these employees are female.
Company B has 250 employees. 48% of these employees are female.
The two companies merge to form one single company.
Calculate the percentage of the employees in the merged company who are female.
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Worked solution
First, calculate the number of female employees in Company A:
\(150 \times 0.60 = 90\) female employees
Next, calculate the number of female employees in Company B:
\(250 \times 0.48 = 120\) female employees
Find the total number of female employees in the merged company:
\(90 + 120 = 210\) female employees
Find the total number of employees in the merged company:
\(150 + 250 = 400\) total employees
Calculate the percentage of female employees in the merged company:
$$\frac{210}{400} \times 100 = 52.5\%$$
Marking scheme
M1 for finding the number of females in Company A: \(150 \times 0.60 = 90\)
M1 for finding the number of females in Company B: \(250 \times 0.48 = 120\)
M1 for a complete method to find the percentage: \(\frac{\text{their } 90 + \text{their } 120}{150 + 250} \times 100\)
A1 for \(52.5\) (or \(52.5\%\))
Question 15 · Structured
4 marks
Solve the equation
$$\frac{4}{x+3} + \frac{3}{2x-1} = 1$$
Show clear algebraic working.
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Worked solution
Multiply all terms by the common denominator \((x + 3)(2x - 1)\) to eliminate the fractions:
\(4(2x - 1) + 3(x + 3) = (x + 3)(2x - 1)\)
Expand both sides of the equation:
LHS: \(8x - 4 + 3x + 9 = 11x + 5\)
RHS: \(2x^2 - x + 6x - 3 = 2x^2 + 5x - 3\)
Set the two expanded expressions equal to each other:
\(2x^2 + 5x - 3 = 11x + 5\)
Rearrange into a standard quadratic equation of the form \(ax^2 + bx + c = 0\):
\(2x^2 + 5x - 11x - 3 - 5 = 0\)
\(2x^2 - 6x - 8 = 0\)
Divide the entire equation by 2:
\(x^2 - 3x - 4 = 0\)
Factorise the quadratic:
\((x - 4)(x + 1) = 0\)
Thus, the solutions are:
\(x = 4\) or \(x = -1\)
Marking scheme
M1 for attempting to clear fractions by multiplying through by the common denominator
M1 for correctly expanding both sides of the equation to obtain \(11x + 5\) and \(2x^2 + 5x - 3\)
M1 for rearranging and simplifying to form a three-term quadratic equation equivalent to \(2x^2 - 6x - 8 = 0\) or \(x^2 - 3x - 4 = 0\)
A1 for both solutions: \(x = 4\) and \(x = -1\)
Question 16 · Structured
4 marks
A ship sails 18 km from Port A on a bearing of \(075^\circ\) to point B. The ship then turns and sails 25 km on a bearing of \(150^\circ\) to point C. Calculate the direct distance from Port A to point C. Give your answer correct to 3 significant figures.
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Worked solution
Let's find the interior angle \(ABC\) of triangle \(ABC\).
The bearing of B from A is \(075^\circ\). A line pointing directly South from B makes an angle of \(75^\circ\) with the line segment \(BA\) (alternate angles with the North-line at A).
The bearing of C from B is \(150^\circ\), which is measured clockwise from the North-line at B. Since South is \(180^\circ\), the line \(BC\) makes an angle of \(180^\circ - 150^\circ = 30^\circ\) with the South-line.
Alternatively, co-interior angles between the North-line at A and the North-line at B add up to \(180^\circ\). Since the bearing is \(075^\circ\), the angle from BA to the North-line at B (anti-clockwise) is \(180^\circ - 75^\circ = 105^\circ\).
The bearing of C from B is \(150^\circ\) clockwise from North.
The direction of BA is \(255^\circ\) clockwise from North.
To 3 significant figures, the distance is \(34.4\text{ km}\).
Marking scheme
M1 for finding the correct interior angle \(\angle ABC = 105^\circ\) (can be shown on a diagram)
M1 for substituting their values into the Cosine Rule: \(AC^2 = 18^2 + 25^2 - 2 \times 18 \times 25 \times \cos(105^\circ)\)
M1 for correctly evaluating \(AC^2\) (approx. \(1181.9\)) or \(AC = \sqrt{1181.9}\)
A1 for \(34.4\) (accept answers in the range \(34.3\) to \(34.4\))
Question 17 · Structured
4 marks
In a sale, the price of a computer is reduced by 20%. The sale price of the computer is £500.
After the sale, the price of the computer is increased back to its normal price before the sale.
This normal price is then deposited into a bank account paying \(r\%\) compound interest per annum.
After 2 years, the amount of money in the bank account is £676.
Work out the value of \(r\).
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Worked solution
Let \(N\) be the normal price of the computer. Since the price is reduced by 20% to £500: \(0.80 \times N = 500\) \(N = \frac{500}{0.80} = 625\)
This normal price of £625 is deposited into a bank account with compound interest rate of \(r\%\) per annum. After 2 years, the value is £676: \(625 \times \left(1 + \frac{r}{100}\right)^2 = 676\)
Divide both sides by 625: \(\left(1 + \frac{r}{100}\right)^2 = \frac{676}{625}\)
Take the square root of both sides: \(1 + \frac{r}{100} = \sqrt{1.0816}\) \(1 + \frac{r}{100} = 1.04\)
Subtract 1 from both sides: \(\frac{r}{100} = 0.04\) \(r = 4\)
Marking scheme
M1 for a method to find the normal price, e.g., \(500 / 0.8\) (to get 625) M1 for setting up the compound interest equation, e.g., \(625 \times (1 + r/100)^2 = 676\) M1 for a method to solve for \(1 + r/100\), e.g., \(\sqrt{676/625}\) A1 for \(r = 4\)
Question 18 · Structured
4 marks
Make \(k\) the subject of the formula:
\(H = \frac{4k - 3}{2 - ek}\)
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Worked solution
Multiply both sides by \((2 - ek)\): \(H(2 - ek) = 4k - 3\)
Expand the brackets: \(2H - eHk = 4k - 3\)
Rearrange to get all terms with \(k\) on one side: \(2H + 3 = 4k + eHk\)
Factorise \(k\) from the right-hand side: \(2H + 3 = k(4 + eH)\)
Divide by \((4 + eH)\) to make \(k\) the subject: \(k = \frac{2H + 3}{4 + eH}\)
Marking scheme
M1 for multiplying both sides by the denominator, e.g., \(H(2 - ek) = 4k - 3\) M1 for expanding brackets correctly, e.g., \(2H - eHk = 4k - 3\) M1 for collecting terms in \(k\) on one side and factorising \(k\), e.g., \(k(4 + eH) = 2H + 3\) A1 for \(k = \frac{2H + 3}{4 + eH}\) (or equivalent, e.g., \(k = \frac{-2H - 3}{-4 - eH}\))
Question 19 · Structured
4 marks
In quadrilateral \(ABCD\), angle \(ADB = 90^\circ\) and angle \(BCD = 90^\circ\).
In right-angled triangle \(BCD\), \(BD\) is the hypotenuse: \(\sin(47^\circ) = \frac{CD}{BD}\) \(CD = BD \times \sin(47^\circ)\) \(CD \approx 6.5628 \times \sin(47^\circ)\) \(CD \approx 6.5628 \times 0.7313537 = 4.8001\text{ m}\)
To 3 significant figures, the length of \(CD\) is \(4.80\text{ m}\).
Marking scheme
M1 for using tangent ratio to find \(BD\), e.g., \(\tan(38^\circ) = \frac{BD}{8.4}\) A1 for \(BD = 6.56(28...)\) M1 for using sine ratio with their \(BD\), e.g., \(CD = BD \times \sin(47^\circ)\) A1 for \(4.80\) (or \(4.8\))
Question 20 · Structured
4 marks
A company bought a new machine for £24 000.
The value of the machine depreciates by 12% each year.
Work out the number of years it takes for the value of the machine to first fall below £10 000.
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Worked solution
Let \(n\) be the number of years. The value of the machine after \(n\) years is given by: \(V = 24000 \times (1 - 0.12)^n = 24000 \times (0.88)^n\)
We want to find the smallest integer \(n\) such that: \(24000 \times (0.88)^n < 10000\)
Let's calculate the value for successive years: For \(n = 5\): \(V = 24000 \times (0.88)^5 \approx 12665.61\)
Since 9808.25 is less than 10 000, it takes 7 years.
Marking scheme
M1 for a correct multiplier of \(0.88\) or an expression like \(24000 \times (0.88)^n\) M1 for a method of trial to find the value at \(n \ge 5\), showing at least one calculation, e.g., \(24000 \times 0.88^5\) M1 for calculating the values for \(n = 6\) and \(n = 7\) A1 for 7
Question 21 · Structured
4 marks
Simplify fully the algebraic fraction:
\(\frac{3x^2 - 10x - 8}{2x^2 - 7x - 4}\)
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Worked solution
Factorise the numerator \(3x^2 - 10x - 8\): We look for two numbers that multiply to \(3 \times (-8) = -24\) and add to \(-10\). These are \(-12\) and \(2\). \(3x^2 - 12x + 2x - 8 = 3x(x - 4) + 2(x - 4) = (3x + 2)(x - 4)\)
Factorise the denominator \(2x^2 - 7x - 4\): We look for two numbers that multiply to \(2 \times (-4) = -8\) and add to \(-7\). These are \(-8\) and \(1\). \(2x^2 - 8x + x - 4 = 2x(x - 4) + 1(x - 4) = (2x + 1)(x - 4)\)
Write the fraction with the factorised terms: \(\frac{(3x + 2)(x - 4)}{(2x + 1)(x - 4)}\)
Cancel the common factor \((x - 4)\): \(\frac{3x + 2}{2x + 1}\)
Marking scheme
M2 for factorising the numerator correctly as \((3x + 2)(x - 4)\) (M1 for \((3x+a)(x+b)\) where \(ab=-8\) or \(3b+a=-10\)) M1 for factorising the denominator correctly as \((2x + 1)(x - 4)\) (or M1 for \((2x+c)(x+d)\) where \(cd=-4\) or \(2d+c=-7\)) A1 for \(\frac{3x + 2}{2x + 1}\)
Question 22 · Structured
4 marks
In triangle \(ABC\), \(AB = 7.2\text{ cm}\), \(BC = 8.5\text{ cm}\) and \(AC = 11.4\text{ cm}\).
Calculate the area of the triangle. Give your answer correct to 3 significant figures.
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Worked solution
First, use the Cosine Rule to find the angle \(B\) (angle \(ABC\)): \(b^2 = a^2 + c^2 - 2ac \cos(B)\) Here, \(b = AC = 11.4\), \(a = BC = 8.5\), and \(c = AB = 7.2\).
Now, calculate the area of the triangle: \(\text{Area} = \frac{1}{2} a c \sin(B) = \frac{1;}{2} \times 8.5 \times 7.2 \times \sin(92.7484^\circ)\) \(\text{Area} \approx 30.6 \times 0.99885 = 30.5648\text{ cm}^2\)
Correct to 3 significant figures, the area is \(30.6\text{ cm}^2\).
Marking scheme
M1 for a correct substitution into the Cosine Rule, e.g., \(11.4^2 = 8.5^2 + 7.2^2 - 2 \times 8.5 \times 7.2 \times \cos(B)\) M1 for a method to calculate \(\cos(B)\), leading to \(\cos(B) = -0.048\) or \(B = 92.7^\circ\) M1 for a method to calculate the area using \(\frac{1}{2} a c \sin(B)\) A1 for \(30.6\)
Question 23 · Structured
4 marks
A right-angled triangle has a base of length \((2x - 3)\text{ cm}\) and a perpendicular height of \((x + 4)\text{ cm}\).
The area of the triangle is \(22\text{ cm}^2\).
Calculate the value of \(x\). Give your answer correct to 3 significant figures.
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Worked solution
The area of a triangle is given by: \(\text{Area} = \frac{1}{2} \times \text{base} \times \text{height}\)
Substitute the given values: \(\frac{1}{2}(2x - 3)(x + 4) = 22\)
Multiply both sides by 2: \((2x - 3)(x + 4) = 44\)
Subtract 44 from both sides to form a quadratic equation: \(2x^2 + 5x - 56 = 0\)
Use the quadratic formula \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\): \(x = \frac{-5 \pm \sqrt{5^2 - 4(2)(-56)}}{2(2)}\) \(x = \frac{-5 \pm \sqrt{25 + 448}}{4} = \frac{-5 \pm \sqrt{473}}{4}\)
Since \(x\) must be positive for the base \(2x - 3\) to be positive: \(x = \frac{-5 + 21.74856}{4} \approx 4.187\)
To 3 significant figures, \(x = 4.19\).
Marking scheme
M1 for setting up the area equation, e.g., \(\frac{1}{2}(2x - 3)(x + 4) = 22\) M1 for expanding and rearranging to form a 3-term quadratic equation, e.g., \(2x^2 + 5x - 56 = 0\) M1 for a correct substitution into the quadratic formula A1 for \(4.19\)
Question 24 · Structured
4 marks
The functions \(f\) and \(g\) are defined as:
\(f(x) = \frac{5}{x - 3}, \quad x \neq 3\)
\(g(x) = 3x + 2\)
(a) Find an expression for \(fg(x)\). Give your answer as a single fraction in its simplest form.
(b) Solve the equation \(fg(x) = x\). Give your answers correct to 3 significant figures.
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M1 for finding \(fg(x)\) as \(\frac{5}{(3x + 2) - 3}\) A1 for simplifying \(fg(x)\) to \(\frac{5}{3x - 1}\) M1 for setting up the equation \(\frac{5}{3x - 1} = x\) and forming the quadratic equation \(3x^2 - x - 5 = 0\) A1 for \(x = 1.47\) and \(x = -1.14\)
Question 25 · Structured
4 marks
Express $$\frac{2}{x^2 - 4} - \frac{1}{x^2 - 2x}$$ as a single fraction in its simplest form.
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Worked solution
First, factorise the denominators of both fractions:
Cancel the common factor of \((x - 2)\) from both the numerator and the denominator:
$$\frac{1}{x(x + 2)}$$
This can also be written as:
$$\frac{1}{x^2 + 2x}$$
Marking scheme
M1: For factorising at least one denominator correctly: \(x^2 - 4 = (x-2)(x+2)\) or \(x^2 - 2x = x(x-2)\) M1: For writing both fractions with a common denominator, e.g., \(\frac{2x - (x+2)}{x(x-2)(x+2)}\) or \(\frac{2(x^2-2x) - (x^2-4)}{(x^2-4)(x^2-2x)}\) A1: For simplifying the numerator to \(x-2\) to get \(\frac{x-2}{x(x-2)(x+2)}\) A1: For the final simplified fraction: \(\frac{1}{x(x+2)}\) or \(\frac{1}{x^2+2x}\)
Paper 2H
Answer all 25 questions. Write your working clearly. Calculators may be used.
25 Question · 100 marks
Question 1 · Structured
4 marks
An investment of £6200 is placed in a savings account. It gains interest at a compound rate of \(r\%\) per year. After 3 years, the total value of the investment is £6822.41. Calculate the value of \(r\). Give your answer to 2 decimal places.
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Worked solution
We use the compound interest formula: \(A = P\left(1 + \frac{r}{100}\right)^t\). Here, \(P = 6200\), \(A = 6822.41\), and \(t = 3\). Substituting these values: \(6200\left(1 + \frac{r}{100}\right)^3 = 6822.41\). Divide both sides by 6200: \(\left(1 + \frac{r}{100}\right)^3 = \frac{6822.41}{6200} = 1.1003887...\). Take the cube root of both sides: \(1 + \frac{r}{100} = \sqrt[3]{1.1003887...} \approx 1.0323999...\). Subtract 1 from both sides: \(\frac{r}{100} = 0.0323999...\). Multiply by 100: \(r \approx 3.24\%\).
Marking scheme
M1: for setting up the correct equation \(6200 \times x^3 = 6822.41\) (where \(x = 1 + r/100\)) M1: for \(x^3 = 1.1003887...\) M1: for \(x = 1.0323999...\) A1: for 3.24
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Worked solution
First, factorise the numerator \(3x^2 - 14x - 5\). We look for two numbers that multiply to \(3 \times (-5) = -15\) and add to \(-14\). These numbers are \(-15\) and \(1\). So, \(3x^2 - 15x + x - 5 = 3x(x - 5) + 1(x - 5) = (3x + 1)(x - 5)\). Next, factorise the denominator \(9x^2 - 1\). This is a difference of two squares: \(9x^2 - 1 = (3x - 1)(3x + 1)\). Now, write the fraction with the factorised forms: \(\frac{(3x + 1)(x - 5)}{(3x - 1)(3x + 1)}\). Cancel the common factor of \((3x + 1)\) from both numerator and denominator: \(\frac{x - 5}{3x - 1}\).
Marking scheme
M1: for factorising numerator into two brackets where one is \((3x + 1)\) or \((x - 5)\) M1: for factorising denominator to \((3x - 1)(3x + 1)\) M1: for showing the cancellation of the common factor \((3x + 1)\) A1: for \(\frac{x - 5}{3x - 1}\)
Question 3 · Structured
4 marks
A drone flies from point \(A\) on a bearing of \(048^{\circ}\) for \(5.2\text{ km}\) to point \(B\). It then flies on a bearing of \(135^{\circ}\) for \(7.8\text{ km}\) to point \(C\). Calculate the direct distance from \(A\) to \(C\). Give your answer to 3 significant figures.
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Worked solution
First, find the interior angle \(ABC\). Let the North line at \(B\) be drawn. The angle between North and the line \(BA\) is \(48^{\circ}\) (alternate angles). The bearing of \(C\) from \(B\) is \(135^{\circ}\). The angle between the South line at \(B\) and \(BA\) is \(48^{\circ}\). The angle between the South line at \(B\) and \(BC\) is \(180^{\circ} - 135^{\circ} = 45^{\circ}\). Thus, the angle \(ABC\) is \(48^{\circ} + 45^{\circ} = 93^{\circ}\). Now, apply the Cosine Rule to find \(AC\): \(AC^2 = AB^2 + BC^2 - 2 \times AB \times BC \times \cos(ABC)\). Substituting the values: \(AC^2 = 5.2^2 + 7.8^2 - 2 \times 5.2 \times 7.8 \times \cos(93^{\circ})\). \(AC^2 = 27.04 + 60.84 - 81.12 \times (-0.052335956)\). \(AC^2 = 87.88 + 4.24549 = 92.12549\). \(AC = \sqrt{92.12549} \approx 9.60\text{ km}\).
Marking scheme
M1: for calculating the correct angle \(ABC = 93^{\circ}\) (or angle shown on diagram) M1: for substituting values correctly into the Cosine Rule: \(5.2^2 + 7.8^2 - 2(5.2)(7.8)\cos(93^{\circ})\) M1: for evaluating the terms to find \(AC^2 \approx 92.1\) A1: for 9.60 (accept answers in range 9.59 to 9.61)
Question 4 · Structured
4 marks
In a sale, all prices are reduced by \(15\%\). A customer has a loyalty card which gives them a further \(10\%\) off the sale price. The customer pays £107.10 for a jacket using their loyalty card. Work out the original price of the jacket before any reductions.
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Worked solution
Let \(P\) be the original price of the jacket. The price after a \(15\%\) reduction is \(0.85P\). The price after a further \(10\%\) reduction is \(0.85P \times 0.90 = 0.765P\). We are given that this final price is £107.10. Therefore, \(0.765P = 107.10\). To find \(P\), divide 107.10 by 0.765: \(P = \frac{107.10}{0.765} = 140\).
Marking scheme
M1: for recognizing the loyalty card price is \(90\%\) of the sale price and calculating \(107.10 \div 0.90 = 119\) or writing \(P \times 0.85 \times 0.90 = 107.10\) M1: for recognizing the sale price is \(85\%\) of the original price and writing \(119 \div 0.85\) or \(P = 107.10 \div 0.765\) M1: for an evaluation step, e.g., finding the intermediate price of 119 or the combined multiplier of 0.765 A1: for 140
Question 5 · Structured
4 marks
Make \(w\) the subject of the formula: \(y = \frac{4 - 3w}{2w + 5}\)
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Worked solution
First, multiply both sides by \((2w + 5)\) to clear the fraction: \(y(2w + 5) = 4 - 3w\). Expand the bracket on the left side: \(2wy + 5y = 4 - 3w\). Next, move all terms containing \(w\) to one side, and all other terms to the opposite side: \(2wy + 3w = 4 - 5y\). Factorise \(w\) out of the left-hand side: \(w(2y + 3) = 4 - 5y\). Finally, divide both sides by \((2y + 3)\) to isolate \(w\): \(w = \frac{4 - 5y}{2y + 3}\).
Marking scheme
M1: for multiplying by \(2w + 5\) to get \(y(2w + 5) = 4 - 3w\) M1: for expanding and rearranging to collect terms in \(w\) on one side, e.g., \(2wy + 3w = 4 - 5y\) M1: for factorising \(w\) to get \(w(2y + 3) = 4 - 5y\) A1: for \(w = \frac{4 - 5y}{2y + 3}\) (or equivalent, e.g., \(w = \frac{5y - 4}{-2y - 3}\))
Question 6 · Structured
4 marks
A right pyramid has a square base \(ABCD\) of side length \(6\text{ cm}\). The vertex of the pyramid is \(V\), and the perpendicular height of the pyramid is \(8\text{ cm}\). Calculate the angle between the edge \(VA\) and the base \(ABCD\). Give your answer to 1 decimal place.
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Worked solution
Let \(M\) be the center of the square base \(ABCD\). The diagonal of the base \(AC\) can be found using Pythagoras' theorem on triangle \(ADC\): \(AC^2 = 6^2 + 6^2 = 72 \implies AC = \sqrt{72} = 6\sqrt{2} \approx 8.485\text{ cm}\). The distance from corner \(A\) to the center \(M\) is half of the diagonal: \(AM = \frac{AC}{2} = \frac{6\sqrt{2}}{2} = 3\sqrt{2} \approx 4.243\text{ cm}\). In the right-angled triangle \(VMA\), the perpendicular height \(VM = 8\text{ cm}\). The angle \(\theta\) between the edge \(VA\) and the base is angle \(VAM\): \(\tan(\theta) = \frac{VM}{AM} = \frac{8}{3\sqrt{2}}\). \(\tan(\theta) \approx 1.8856\). \(\theta = \tan^{-1}(1.8856) \approx 62.1^{\circ}\).
Marking scheme
M1: for finding the diagonal of the base: \(AC = \sqrt{6^2 + 6^2} = \sqrt{72}\) M1: for finding the half-diagonal: \(AM = \frac{\sqrt{72}}{2} = 3\sqrt{2} \approx 4.24\) M1: for \(\tan(\theta) = \frac{8}{3\sqrt{2}}\) or equivalent trigonometric setup A1: for 62.1 (accept answers in range 62.0 to 62.1)
Question 7 · Structured
4 marks
A rectangle has a length of \((2x + 3)\text{ cm}\) and a width of \((x - 1)\text{ cm}\). The area of the rectangle is \(45\text{ cm}^2\). Work out the value of \(x\). Show your working clearly and give your answer to 3 significant figures.
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Worked solution
The area of a rectangle is length multiplied by width: \((2x + 3)(x - 1) = 45\). Expand the brackets: \(2x^2 - 2x + 3x - 3 = 45 \implies 2x^2 + x - 3 = 45\). Rearrange into standard quadratic form \(ax^2 + bx + c = 0\): \(2x^2 + x - 48 = 0\). Use the quadratic formula \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\) with \(a = 2\), \(b = 1\), and \(c = -48\): \(x = \frac{-1 \pm \sqrt{1^2 - 4(2)(-48)}}{2(2)}\). \(x = \frac{-1 \pm \sqrt{1 + 384}}{4} = \frac{-1 \pm \sqrt{385}}{4}\). Since the width \((x-1)\) must be positive, \(x\) must be greater than 1. Thus, we take the positive root: \(x = \frac{-1 + \sqrt{385}}{4} \approx \frac{-1 + 19.6214}{4} = 4.6553...\). To 3 significant figures, \(x = 4.66\).
Marking scheme
M1: for setting up the equation \((2x + 3)(x - 1) = 45\) M1: for expanding and rearranging to \(2x^2 + x - 48 = 0\) M1: for substituting into the quadratic formula: \(x = \frac{-1 \pm \sqrt{1^2 - 4(2)(-48)}}{4}\) A1: for 4.66 (accept 4.65 to 4.67)
Question 8 · Structured
4 marks
In a company, \(60\%\) of the employees are female. During a year, the number of female employees increases by \(15\%\) and the number of male employees decreases by \(10\%\). Calculate the percentage change in the total number of employees in the company.
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Worked solution
Let the total number of employees initially be \(T\). The number of female employees is \(0.60T\) and the number of male employees is \(0.40T\). After the changes: The new number of female employees is \(0.60T \times 1.15 = 0.69T\). The new number of male employees is \(0.40T \times 0.90 = 0.36T\). The new total number of employees is \(0.69T + 0.36T = 1.05T\). The percentage change in the total number of employees is \(\frac{1.05T - T}{T} \times 100 = 5\%\).
Marking scheme
M1: for identifying that females represent \(60\%\) and males represent \(40\%\) (or using a numerical base like 100, so 60 females and 40 males) M1: for calculating the new number of females \(0.60 \times 1.15 = 0.69\) (or 69) or the new number of males \(0.40 \times 0.90 = 0.36\) (or 36) M1: for finding the new total: \(0.69 + 0.36 = 1.05\) (or 105) A1: for 5 (or 5% increase)
Question 9 · structured
4 marks
Make \(t\) the subject of the formula \(p = \frac{5 - 3t}{2t + a}\).
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Worked solution
First, multiply both sides by the denominator to clear the fraction: \(p(2t + a) = 5 - 3t\). Next, expand the brackets: \(2pt + ap = 5 - 3t\). Collect all terms containing \(t\) on one side of the equation and the other terms on the opposite side: \(2pt + 3t = 5 - ap\). Factorise \(t\) from the left side: \(t(2p + 3) = 5 - ap\). Finally, divide both sides by \(2p + 3\) to isolate \(t\): \(t = \frac{5 - ap}{2p + 3}\).
Marking scheme
M1 for multiplying by \(2t + a\) to get \(p(2t + a) = 5 - 3t\). M1 for expanding brackets and grouping terms in \(t\) on one side. M1 for factorising \(t\) to get \(t(2p + 3) = 5 - ap\). A1 for the correct final formula \(t = \frac{5 - ap}{2p + 3}\) (or equivalent, e.g. \(t = \frac{ap - 5}{-2p - 3}\)).
Question 10 · structured
4 marks
A cuboid \(ABCDEFGH\) has a horizontal rectangular base \(ABCD\) with \(AB = 12\text{ cm}\) and \(BC = 5\text{ cm}\). The vertical edge \(AE = 8\text{ cm}\). Calculate the angle between the diagonal \(EC\) and the base \(ABCD\). Give your answer correct to 1 decimal place.
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Worked solution
First, find the length of the base diagonal \(AC\) using Pythagoras' theorem on the horizontal right-angled triangle \(ABC\): \(AC = \sqrt{AB^2 + BC^2} = \sqrt{12^2 + 5^2} = \sqrt{144 + 25} = \sqrt{169} = 13\text{ cm}\). The diagonal \(EC\) makes an angle with the base \(ABCD\) which is the angle \(\angle ECA\). In the vertical right-angled triangle \(EAC\), the side opposite to this angle is \(AE = 8\text{ cm}\) and the adjacent side is \(AC = 13\text{ cm}\). Using trigonometry: \(\tan(\angle ECA) = \frac{AE}{AC} = \frac{8}{13}\). Thus, \(\angle ECA = \arctan\left(\frac{8}{13}\right) \approx 31.6075^\circ\). Correct to 1 decimal place, the angle is \(31.6^\circ\).
Marking scheme
M1 for using Pythagoras to find the base diagonal: \(12^2 + 5^2\) or \(\sqrt{12^2 + 5^2}\). A1 for \(AC = 13\). M1 for \(\tan(\theta) = \frac{8}{13}\) (or using their \(AC\)). A1 for \(31.6\) (accept answers in the range 31.6 to 31.61).
Question 11 · structured
4 marks
A sum of £8000 is invested in a savings account. The investment earns compound interest at a rate of \(R\%\) per annum. At the end of 3 years, the value of the investment is £9261. Calculate the value of \(R\).
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Worked solution
The formula for compound interest is \(\text{Value} = P\left(1 + \frac{R}{100}\right)^n\). Substituting the given values: \(9261 = 8000\left(1 + \frac{R}{100}\right)^3\). Divide both sides by 8000: \(\left(1 + \frac{R}{100}\right)^3 = \frac{9261}{8000} = 1.157625\). Take the cube root of both sides: \(1 + \frac{R}{100} = \sqrt[3]{1.157625} = 1.05\). Subtract 1 from both sides: \(\frac{R}{100} = 0.05\). Multiply by 100 to find \(R\): \(R = 5\).
Marking scheme
M1 for setting up the correct compound interest equation: \(8000(1 + R/100)^3 = 9261\). M1 for simplifying to \((1 + R/100)^3 = 1.157625\) (or \(\frac{9261}{8000}\)). M1 for taking the cube root: \(1 + R/100 = 1.05\). A1 for \(R = 5\).
Question 12 · structured
4 marks
Solve the equation \(\frac{5}{x+2} + \frac{3}{x-1} = 2\). Show clear algebraic working. Give your solutions correct to 3 significant figures.
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Worked solution
Multiply all terms by the common denominator \((x+2)(x-1)\) to eliminate the fractions: \(5(x-1) + 3(x+2) = 2(x+2)(x-1)\). Expand both sides of the equation: \(5x - 5 + 3x + 6 = 2(x^2 + x - 2)\), which simplifies to \(8x + 1 = 2x^2 + 2x - 4\). Rearrange the equation into standard quadratic form \(ax^2 + bx + c = 0\): \(2x^2 - 6x - 5 = 0\). Use the quadratic formula \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\) with \(a = 2\), \(b = -6\), and \(c = -5\): \(x = \frac{-(-6) \pm \sqrt{(-6)^2 - 4(2)(-5)}}{2(2)}\), which simplifies to \(x = \frac{6 \pm \sqrt{36 + 40}}{4} = \frac{6 \pm \sqrt{76}}{4}\). This gives two solutions: \(x = \frac{6 + 8.7178}{4} \approx 3.679\) and \(x = \frac{6 - 8.7178}{4} \approx -0.6794\). Correct to 3 significant figures, the solutions are \(3.68\) and \(-0.679\).
Marking scheme
M1 for a correct equation without fractions: \(5(x-1) + 3(x+2) = 2(x+2)(x-1)\). M1 for expanding and simplifying to a standard quadratic equation: \(2x^2 - 6x - 5 = 0\). M1 for a correct substitution of their quadratic coefficients into the quadratic formula. A1 for both answers correct to 3 significant figures: \(3.68\) and \(-0.679\) (accept \(3.679\) and \(-0.6794\)).
Question 13 · structured
4 marks
In triangle \(ABC\), \(AB = 7\text{ cm}\), \(BC = 10\text{ cm}\) and the area of the triangle is \(28\text{ cm}^2\). Given that angle \(ABC\) is obtuse, calculate the length of \(AC\). Give your answer correct to 3 significant figures.
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Worked solution
First, use the formula for the area of a triangle: \(\text{Area} = \frac{1}{2} a c \sin(B)\). Substituting the given values: \(28 = \frac{1}{2} \times 10 \times 7 \times \sin(B)\), which simplifies to \(28 = 35 \sin(B)\). Therefore, \(\sin(B) = \frac{28}{35} = 0.8\). Since angle \(ABC\) is obtuse, the angle must be between \(90^\circ\) and \(180^\circ\): \(B = 180^\circ - \arcsin(0.8) \approx 180^\circ - 53.13^\circ = 126.87^\circ\). Now, use the cosine rule to find the length of \(AC\): \(AC^2 = AB^2 + BC^2 - 2 \cdot AB \cdot BC \cdot \cos(B)\). Since \(\cos(126.87^\circ) = -0.6\), we have: \(AC^2 = 7^2 + 10^2 - 2(7)(10)(-0.6) = 49 + 100 + 84 = 233\). Thus, \(AC = \sqrt{233} \approx 15.264\text{ cm}\). Correct to 3 significant figures, \(AC = 15.3\text{ cm}\).
Marking scheme
M1 for substituting area values into \(\frac{1}{2} a c \sin(B)\): \(28 = \frac{1}{2} \times 10 \times 7 \sin(B)\). A1 for finding the obtuse angle \(B \approx 126.87^\circ\) (or for stating \(\sin(B) = 0.8\) and \(\cos(B) = -0.6\)). M1 for substituting their values into the cosine rule: \(AC^2 = 7^2 + 10^2 - 2(7)(10)\cos(126.87^\circ)\). A1 for \(15.3\) (accept answers in the range 15.2 to 15.3).
Question 14 · structured
4 marks
In 2021, the profit of a company was \(15\%\) more than its profit in 2020. In 2022, the profit of the company was \(8\%\) less than its profit in 2021. The profit of the company in 2022 was £243,340. Calculate the profit of the company in 2020.
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Worked solution
Let \(P\) represent the profit of the company in 2020. In 2021, the profit was \(1.15 \times P\). In 2022, the profit was \(0.92 \times (1.15 \times P)\), which simplifies to \(1.058 \times P\). We are given that the profit in 2022 was £243,340, so we set up the equation: \(1.058 \times P = 243340\). Solving for \(P\): \(P = \frac{243340}{1.058} = 230000\). Therefore, the profit in 2020 was £230,000.
Marking scheme
M1 for writing an expression for the profit in 2021, e.g. \(1.15 \times P\). M1 for combining both percentage changes, e.g. \(1.15 \times 0.92 = 1.058\). M1 for setting up the equation \(1.058 \times P = 243340\) and dividing: \(\frac{243340}{1.058}\). A1 for \(230000\).
Question 15 · structured
4 marks
A drone flies from base \(B\) on a bearing of \(055^\circ\) for \(8\text{ km}\) to point \(C\). It then flies on a bearing of \(165^\circ\) for \(12\text{ km}\) to point \(D\). Calculate the distance \(BD\). Give your answer correct to 3 significant figures.
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Worked solution
First, find the interior angle \(\angle BCD\) in triangle \(BCD\). The bearing of \(C\) from \(B\) is \(055^\circ\). The back bearing (the direction from \(C\) to \(B\)) is \(055^\circ + 180^\circ = 235^\circ\). Since the bearing of \(D\) from \(C\) is \(165^\circ\), the interior angle \(\angle BCD\) is the difference between these two directions: \(\angle BCD = 235^\circ - 165^\circ = 70^\circ\). Now, we can apply the cosine rule to triangle \(BCD\) to find the distance \(BD\): \(BD^2 = BC^2 + CD^2 - 2 \cdot BC \cdot CD \cdot \cos(\angle BCD)\). Substitute \(BC = 8\), \(CD = 12\), and \(\angle BCD = 70^\circ\): \(BD^2 = 8^2 + 12^2 - 2(8)(12)\cos(70^\circ)\), \(BD^2 = 64 + 144 - 192\cos(70^\circ)\), \(BD^2 = 208 - 192(0.34202)\), \(BD^2 = 208 - 65.668 = 142.332\). Thus, \(BD = \sqrt{142.332} \approx 11.93\text{ km}\). Correct to 3 significant figures, the distance is \(11.9\text{ km}\).
Marking scheme
M1 for finding the interior angle \(\angle BCD = 70^\circ\) (or showing equivalent working with parallel lines and bearings). M1 for a correct substitution into the Cosine Rule: \(BD^2 = 8^2 + 12^2 - 2 \times 8 \times 12 \cos(70^\circ)\). M1 for evaluating \(BD^2\) to at least 3 significant figures (e.g. 142 or 142.3). A1 for \(11.9\) (accept answers in the range 11.9 to 12.0).
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Worked solution
First, factorise each quadratic expression: 1. \(2x^2 - 5x - 3 = (2x + 1)(x - 3)\). 2. \(2x^2 - 18 = 2(x^2 - 9) = 2(x - 3)(x + 3)\). 3. \(2x^2 + 7x + 3 = (2x + 1)(x + 3)\). 4. \(x^2 + 6x + 9 = (x + 3)^2\). Substitute these factorised forms back into the expression and change the division to multiplication by the reciprocal of the second fraction: \(\frac{(2x + 1)(x - 3)}{2(x - 3)(x + 3)} \times \frac{(x + 3)^2}{(2x + 1)(x + 3)}\). Combine the terms into a single fraction: \(\frac{(2x + 1)(x - 3)(x + 3)^2}{2(x - 3)(x + 3)(2x + 1)(x + 3)} = \frac{(2x + 1)(x - 3)(x + 3)^2}{2(2x + 1)(x - 3)(x + 3)^2}\). Cancel out all identical terms in the numerator and denominator: \((2x+1)\), \((x-3)\), and \((x+3)^2\) all cancel out, leaving \(\frac{1}{2}\).
Marking scheme
M1 for factorising either \(2x^2 - 5x - 3\) to \((2x + 1)(x - 3)\) or \(2x^2 - 18\) to \(2(x - 3)(x + 3)\). M1 for factorising either \(2x^2 + 7x + 3\) to \((2x + 1)(x + 3)\) or \(x^2 + 6x + 9\) to \((x + 3)^2\). M1 for inverting the divisor and multiplying: \(\frac{(2x + 1)(x - 3)}{2(x - 3)(x + 3)} \times \frac{(x + 3)^2}{(2x + 1)(x + 3)}\). A1 for \(\frac{1}{2}\) (or \(0.5\)).
Question 17 · Structured
4 marks
At the start of the year, Arthur invested £\(x\) in Account A and £\((x + 4000)\) in Account B. During the year, the money in Account A increased by 12%. The money in Account B decreased by 5%. At the end of the year, the total value of the money in both accounts was £28,640. Work out the value of \(x\).
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Worked solution
Let the amount in Account A be \(x\) and in Account B be \(x + 4000\). At the end of the year, the value in Account A is \(1.12x\) and the value in Account B is \(0.95(x + 4000)\). We are given that the sum of these values is £28,640. Setting up the equation: \(1.12x + 0.95(x + 4000) = 28640\). Expanding and simplifying: \(1.12x + 0.95x + 3800 = 28640\), which gives \(2.07x = 24840\). Solving for \(x\): \(x = 12000\).
Marking scheme
M1: for expressing the end of year value of Account A as \(1.12x\) or Account B as \(0.95(x + 4000)\). M1: for setting up the correct equation \(1.12x + 0.95(x + 4000) = 28640\). M1: for simplifying to the form \(2.07x = 24840\). A1: for 12000 (accept £12,000).
M1: for factorising the numerator as \((2x - 3)(x + 4)\). M1: for factorising the denominator as \(3(x^2 - 16)\) or \(3(x - 4)(x + 4)\). M1: for writing the fully factorised fraction. A1: for \(\frac{2x - 3}{3(x - 4)}\) or \(\frac{2x - 3}{3x - 12}\).
Question 19 · Structured
4 marks
The diagram shows a right rectangular prism (cuboid) \(ABCD-EFGH\). The base \(ABCD\) is a rectangle with \(AB = 8\text{ cm}\) and \(BC = 6\text{ cm}\). The vertices \(E, F, G, H\) are vertically above \(A, B, C, D\) respectively. The diagonal \(BH\) of the cuboid makes an angle of \(40^\circ\) with the horizontal base \(ABCD\). Calculate the height of the cuboid, \(DH\). Give your answer correct to 3 significant figures.
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Worked solution
First, calculate the length of the base diagonal \(BD\). Since \(ABCD\) is a rectangle with \(AB = 8\text{ cm}\) and \(AD = 6\text{ cm}\), using Pythagoras' theorem: \(BD = \sqrt{8^2 + 6^2} = \sqrt{100} = 10\text{ cm}\). The height \(DH\) is vertical, so triangle \(BDH\) is a right-angled triangle at \(D\). We are given that angle \(HBD = 40^\circ\). Using trigonometry: \(\tan(40^\circ) = \frac{DH}{BD} = \frac{DH}{10}\). Therefore, \(DH = 10 \times \tan(40^\circ) \approx 8.390996...\text{ cm}\). Correct to 3 significant figures, \(DH = 8.39\text{ cm}\).
Marking scheme
M1: for a method to find the diagonal \(BD\), e.g., \(\sqrt{8^2 + 6^2}\). A1: for \(BD = 10\). M1: for using \(\tan(40^\circ) = \frac{DH}{10}\) or equivalent. A1: for 8.39 (accept answers in range 8.39 - 8.40).
Question 20 · Structured
4 marks
During a sale, a shop reduces all prices by 15%. An additional discount of 10% off the sale price is given to customers who pay with a store card. Mrs. Patel buys a coat using her store card and pays £68.85. Work out the normal price of the coat.
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Worked solution
Let the normal price of the coat be \(x\) pounds. The price after a 15% reduction is \(0.85x\). The price after an additional 10% reduction is \(0.85x \times 0.90 = 0.765x\). Setting up the equation: \(0.765x = 68.85\). Solving for \(x\): \(x = \frac{68.85}{0.765} = 90\). Thus, the normal price of the coat is £90.
Marking scheme
M1: for multiplying 0.85 by 0.90 (to get 0.765) or for finding the price before card discount, i.e., \(68.85 \div 0.90 = 76.50\). M1: for setting up the equation \(0.765x = 68.85\) or \(0.85y = 76.50\). M1: for \(68.85 \div 0.765\) or \(76.50 \div 0.85\). A1: for 90.
Question 21 · Structured
4 marks
Make \(w\) the subject of the formula \(t = \frac{3 - 2w}{5w + 4}\).
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Worked solution
First, multiply both sides by \((5w + 4)\) to clear the fraction: \(t(5w + 4) = 3 - 2w\). Expand the left side: \(5wt + 4t = 3 - 2w\). Move all terms involving \(w\) to one side: \(5wt + 2w = 3 - 4t\). Factorise \(w\) on the left side: \(w(5t + 2) = 3 - 4t\). Divide by \((5t + 2)\) to solve for \(w\): \(w = \frac{3 - 4t}{5t + 2}\).
Marking scheme
M1: for multiplying both sides by the denominator, e.g., \(t(5w + 4) = 3 - 2w\). M1: for expanding and collecting terms with \(w\) on one side, e.g., \(5wt + 2w = 3 - 4t\). M1: for factorising \(w\), e.g., \(w(5t + 2) = 3 - 4t\). A1: for \(w = \frac{3 - 4t}{5t + 2}\) (or equivalent, e.g., \(w = \frac{4t - 3}{-5t - 2}\)).
Question 22 · Structured
4 marks
In triangle \(ABC\), \(AB = 7\text{ cm}\), \(BC = 12\text{ cm}\), and the area of the triangle is \(35\text{ cm}^2\). Given that angle \(ABC\) is obtuse, calculate the length of \(AC\). Give your answer correct to 3 significant figures.
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Worked solution
Using the area formula: \(\text{Area} = \frac{1}{2} a c \sin(B)\), we have \(35 = \frac{1}{2} \times 12 \times 7 \times \sin(ABC)\). This simplifies to \(35 = 42 \sin(ABC)\), so \(\sin(ABC) = \frac{35}{42} = \frac{5}{6}\). Since the angle \(ABC\) is obtuse, \(ABC = 180^\circ - \arcsin(5/6) \approx 180^\circ - 56.443^\circ = 123.557^\circ\). Now, use the Cosine Rule to find the length of \(AC\): \(AC^2 = AB^2 + BC^2 - 2 \cdot AB \cdot BC \cdot \cos(ABC)\). Substituting the values: \(AC^2 = 7^2 + 12^2 - 2 \times 7 \times 12 \times \cos(123.557^\circ) = 49 + 144 - 168 \times (-0.55277) = 193 + 92.865 = 285.865\). Taking the square root: \(AC = \sqrt{285.865} \approx 16.9075...\text{ cm}\). Correct to 3 significant figures, \(AC = 16.9\text{ cm}\).
Marking scheme
M1: for setting up the area equation \(\frac{1}{2} \times 12 \times 7 \times \sin(B) = 35\). M1: for finding the obtuse angle \(ABC \approx 123.6^\circ\) or for obtaining \(\cos(ABC) = -\frac{\sqrt{11}}{6}\). M1: for substituting values into the Cosine Rule, e.g., \(AC^2 = 7^2 + 12^2 - 2(7)(12)\cos(123.6^\circ)\). A1: for 16.9 (accept answers in range 16.9 - 17.0).
Question 23 · Structured
4 marks
Solve the equation \(\frac{5}{x+2} + \frac{3}{x-1} = 2\). Show clear algebraic working and give your solutions correct to 3 significant figures.
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Worked solution
Multiply each term by the common denominator \((x+2)(x-1)\): \(5(x-1) + 3(x+2) = 2(x+2)(x-1)\). Expand the brackets: \(5x - 5 + 3x + 6 = 2(x^2 + x - 2)\), which simplifies to \(8x + 1 = 2x^2 + 2x - 4\). Rearrange into standard quadratic form: \(2x^2 - 6x - 5 = 0\). Solve using the quadratic formula: \(x = \frac{-(-6) \pm \sqrt{(-6)^2 - 4(2)(-5)}}{2(2)} = \frac{6 \pm \sqrt{36 + 40}}{4} = \frac{6 \pm \sqrt{76}}{4}\). This gives \(x = \frac{6 + 8.7178}{4} \approx 3.679\) and \(x = \frac{6 - 8.7178}{4} \approx -0.679\).
Marking scheme
M1: for writing the LHS over a single common denominator or multiplying all terms by \((x+2)(x-1)\). M1: for expanding and simplifying to a quadratic equation, e.g., \(8x + 1 = 2(x^2 + x - 2)\). M1: for rearranging to a correct quadratic equation, e.g., \(2x^2 - 6x - 5 = 0\). A1: for both 3.68 and -0.679.
Question 24 · Structured
4 marks
Ship \(S\) sails 15 km from Port \(A\) on a bearing of \(060^\circ\) to point \(B\). The ship then sails 22 km from \(B\) on a bearing of \(130^\circ\) to point \(C\). Calculate the direct distance from Port \(A\) to point \(C\). Give your answer correct to 3 significant figures.
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Worked solution
The bearing of \(B\) from \(A\) is \(060^\circ\). This means the back bearing of \(A\) from \(B\) is \(060^\circ + 180^\circ = 240^\circ\). Since the bearing of \(C\) from \(B\) is \(130^\circ\), the interior angle \(\angle ABC\) of the triangle is the difference between these bearings: \(\angle ABC = 240^\circ - 130^\circ = 110^\circ\). We now use the Cosine Rule in triangle \(ABC\) to find \(AC\): \(AC^2 = AB^2 + BC^2 - 2 \cdot AB \cdot BC \cdot \cos(\angle ABC)\). Substituting the given lengths: \(AC^2 = 15^2 + 22^2 - 2 \times 15 \times 22 \times \cos(110^\circ) = 225 + 484 - 660 \times (-0.34202) = 709 + 225.733 = 934.733\). Taking the square root: \(AC = \sqrt{934.733} \approx 30.573...\text{ km}\). Correct to 3 significant figures, the distance is \(30.6\text{ km}\).
Marking scheme
M1: for finding the interior angle \(\angle ABC = 110^\circ\) (or showing a diagram with correct angle calculations). A1: for \(\angle ABC = 110^\circ\). M1: for substituting values into the Cosine Rule: \(AC^2 = 15^2 + 22^2 - 2 \times 15 \times 22 \times \cos(110^\circ)\). A1: for 30.6 (accept answers in range 30.5 - 30.6).
Question 25 · Structured
4 marks
A sum of money is invested in three different savings schemes, \(P\), \(Q\) and \(R\), in the ratio \(4 : 5 : 3\) respectively.
Over one year: * the value of the investment in scheme \(P\) increases by \(8\%\) * the value of the investment in scheme \(Q\) decreases by \(4\%\) * the value of the investment in scheme \(R\) increases by \(15\%\)
Work out the overall percentage increase in the total amount invested.
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Worked solution
Let the amount of money invested in schemes \(P\), \(Q\) and \(R\) be represented by \(400\), \(500\) and \(300\) respectively.
1. **Calculate the total initial investment:** \[\text{Total initial investment} = 400 + 500 + 300 = 1200\]
2. **Calculate the changes in value for each scheme:** * For scheme \(P\): \(400 \times 0.08 = +32\) * For scheme \(Q\): \(500 \times (-0.04) = -20\) * For scheme \(R\): \(300 \times 0.15 = +45\)
3. **Calculate the net change in the total investment:** \[\text{Net change} = +32 - 20 + 45 = +57\]
Alternatively, using algebraic representation with \(x\): Let the investments be \(4x\), \(5x\) and \(3x\), giving a total of \(12x\). * New value of \(P = 4x \times 1.08 = 4.32x\) * New value of \(Q = 5x \times 0.96 = 4.80x\) * New value of \(R = 3x \times 1.15 = 3.45x\) * Total new value \(= 4.32x + 4.80x + 3.45x = 12.57x\) * Percentage increase \(= \frac{12.57x - 12x}{12x} \times 100 = 4.75\%\)
Marking scheme
**M1**: For a method to represent the investments using a common variable or specific values in the ratio \(4:5:3\) (e.g., \(4x, 5x, 3x\) or \(400, 500, 300\)), and stating the total initial investment as \(12x\) or \(1200\).
**M1**: For calculating the change or the new value for at least two of the schemes (e.g., \(400 \times 0.08 = 32\) or \(432\), and \(500 \times (-0.04) = -20\) or \(480\)).
**M1**: For a complete method to find the overall percentage increase, e.g., \(\frac{32 - 20 + 45}{1200} \times 100\) or \(\frac{1257 - 1200}{1200} \times 100\).
**A1**: For \(4.75\) (or \(4.75\%\), or equivalent fraction/mixed number like \(\frac{19}{4}\) or \(4\frac{3}{4}\)).
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